To make my previous response more accurate: the difference in OS versions might affect product's configuration databases if you decided to go with the VBO server migration itself.
With a clean installation, to move only the repository data you can follow the steps described in the KB. While our QC has not specifically tested moving repositories between Server 2016 and 2019, we expect everything to go smoothly. (As always, it's recommended to keep a copy of your current production data until you ensure that the new VBO server is up and running and all backup databases are in the correct state.)

Previous restore points will be available as soon as the organization is added to the scope (right-click it and check point-in-time states).